Fugitive Gluing
The following question and answer section focuses on creative bindery techniques, as well as tips and ideas that can help make your business more competitive and profitable.
E-Z Release Glue Application
What Can E-Z Release Glue Be Used For?
Managing variable adhesion and chemical reactions is important. Some E-Z release glue solvents, such as ammonia, dissolve aqueous and other coatings and result in permanent adhesion.
Solving the Glue Puzzle
Remoistenable Glue (Remoist)
Many remoistenable glue jobs are done inline with other binding processes. For example, you may apply remoist glue, stop-perforate the sheet, apply seam glue to form a pocket, fold it (barrel folds, accordions and gatefolds), apply wafer/clip seals, slit it and keep the job in mail-sort order. .. all inline.
Common applications: Envelopes, direct mail response vehicles (2-ply BRCs - Business Reply Cards).
Seam (Permanent)
Resin-based permanent glues are applied cold and provide a good bond with a relatively small amount of residue. Hot melt glues set nearly instantaneously. Permanent glue needs to bite into the paper, so the harder the surface, the more difficult it is to penetrate the sheet and create good adhesion.
Common Applications: Envelopes, direct mail response vehicles.
E-Z Release
Latex E-Z release glues require long setup times (3 to 4 minutes) and tend to spread when the opposing sheet is tightly squeezed. Their curing period is really 24-hours even though they appear to be dry after 10 minutes. Oil-based E-Z release glues have a shorter curing time. Common Applications: Self-mailers, wafer/clip sealing substitute, temporarily hold forms together for other operations (i.e. saddle stitching).
Spot Gluing in Trim-Off Areas
Why Spot Glue in Trim-Off Margin Areas?
Most gate folds, over & over folds, and accordion folds will unravel during the saddle stitching or perfect binding processes unless they are held together by glue. However, products often need to be glue-free when they reach the end-user. Spot glue, properly engineered and applied in trim-off margin areas, will accommodate production efficiency needs, but will be completely removed after downstream operations.
The Ugly Truth ...
A glue dot will spread, no matter how small it is. Practically speaking, glue usually spreads more than 1/8". Therefore, if paper efficiency is a major concern, as it almost always is on long run jobs, the most efficient printing layout may not be good for spot gluing. If the glue dot it too close to the edge of the sheet, it will spread beyond the paper causing individual sheets to stick together in a "brick." If the dot is too close to the final image area, the glue will not be completely trimmed out.
Suggested Guidelines.
Allow at least 3/8" (1/2" preferred) trim-off area in the non "jog-to" end of the product and apply spot glue there. Allow for a 1/8" margin on the "jog-to" end and don't apply spot glue there. If these margins aren't possible for your job, consider using latex E-Z release instead of permanent spot glue. If you go this route, you will likely need to apply glue on both the jog-to and nonjog-to ends of the product due to E-Z release's weaker adhesive properties. Also, advise your customer that you may get some E-Z release glue remnants creeping into the final trimmed product.
What Can E-Z Release Glue Be Used For?
- It's an economical and attractive substitute for wafer/clip sealing. (Properly manufactured products work great in the US/CAN mail stream.)
- It keeps fold-outs and gatefolds from unraveling during binding operations
- It holds products together so they can be automatically inserted (i.e. consumer product instruction sheets in to bottles or boxes)
- It's great for pharmaceutical and/or miniature folded products
Managing variable adhesion and chemical reactions is important. Some E-Z release glue solvents, such as ammonia, dissolve aqueous and other coatings and result in permanent adhesion.
Solving the Glue Puzzle
Remoistenable Glue (Remoist)
Many remoistenable glue jobs are done inline with other binding processes. For example, you may apply remoist glue, stop-perforate the sheet, apply seam glue to form a pocket, fold it (barrel folds, accordions and gatefolds), apply wafer/clip seals, slit it and keep the job in mail-sort order. .. all inline.
Common applications: Envelopes, direct mail response vehicles (2-ply BRCs - Business Reply Cards).
Seam (Permanent)
Resin-based permanent glues are applied cold and provide a good bond with a relatively small amount of residue. Hot melt glues set nearly instantaneously. Permanent glue needs to bite into the paper, so the harder the surface, the more difficult it is to penetrate the sheet and create good adhesion.
Common Applications: Envelopes, direct mail response vehicles.
E-Z Release
Latex E-Z release glues require long setup times (3 to 4 minutes) and tend to spread when the opposing sheet is tightly squeezed. Their curing period is really 24-hours even though they appear to be dry after 10 minutes. Oil-based E-Z release glues have a shorter curing time. Common Applications: Self-mailers, wafer/clip sealing substitute, temporarily hold forms together for other operations (i.e. saddle stitching).
Spot Gluing in Trim-Off Areas
Why Spot Glue in Trim-Off Margin Areas?
Most gate folds, over & over folds, and accordion folds will unravel during the saddle stitching or perfect binding processes unless they are held together by glue. However, products often need to be glue-free when they reach the end-user. Spot glue, properly engineered and applied in trim-off margin areas, will accommodate production efficiency needs, but will be completely removed after downstream operations.
The Ugly Truth ...
A glue dot will spread, no matter how small it is. Practically speaking, glue usually spreads more than 1/8". Therefore, if paper efficiency is a major concern, as it almost always is on long run jobs, the most efficient printing layout may not be good for spot gluing. If the glue dot it too close to the edge of the sheet, it will spread beyond the paper causing individual sheets to stick together in a "brick." If the dot is too close to the final image area, the glue will not be completely trimmed out.
Suggested Guidelines.
Allow at least 3/8" (1/2" preferred) trim-off area in the non "jog-to" end of the product and apply spot glue there. Allow for a 1/8" margin on the "jog-to" end and don't apply spot glue there. If these margins aren't possible for your job, consider using latex E-Z release instead of permanent spot glue. If you go this route, you will likely need to apply glue on both the jog-to and nonjog-to ends of the product due to E-Z release's weaker adhesive properties. Also, advise your customer that you may get some E-Z release glue remnants creeping into the final trimmed product.